Ink jet printing is a conventional technique by which printing is accomplished without contact between the printhead and the substrate, or medium, on which the desired print characters are deposited. Such printing is accomplished by ejecting ink from an ink jet printhead of a printing apparatus via numerous methods which employ, for example, pressurized nozzles, electrostatic fields, piezo-electric elements and/or heaters for vapor phase droplet formation.
Recently, there has been a desire for a hand-held printer, which utilizes the same ink jet printing technology. Performance of a conventional printhead relies typically on proper maintenance steps to insure the nozzles of the printhead do not dry up or clog. In addition, “spitting” or firing the printhead allows the heater to maintain proper temperatures. Improperly maintained printheads can cause noticeable banding and light/dark regions throughout a printed image. Periodic spitting of the nozzles in the spit station is one typical method for preventing or curing reliability problems caused by nozzle inactivity. Spitting is the ejection of non-printing ink drops during printing operations and during routing servicing of the print cartridge. Typically, spitting is done in a spittoon. However, a hand-held ink jet printer may not have space for a spittoon or dedicated maintenance station. For example, the maintenance station may be part of the cradle/docking station of the hand-held ink jet printer. As such, while a conventional printer can perform maintenance anytime without affecting print quality, position is lost with a hand-held printer when performing maintenance since a hand-held printer would require to be lifted off the media and placed in a cradle to service the printheads. This can place a limitation on the user on how long they can print before stopping the job and performing maintenance. In addition, since position may be lost during the maintenance operation, it is difficult to continue the printed pattern. Depending on the printing speed in which nozzles fire, the printed pattern may be limited to a few feet. For many users, this will be unacceptable. One solution known in the art to attempt to overcome this opportunity for improvement is to fire the individual nozzle when a pre-determined time has elapsed between firings of the same nozzle while performing a print job.
In order for the hand-held ink jet printer to resemble a conventional ink printer in shape and size, the hand-held printer has space limitations and as such minimal complexity in design. As such, the hand-held ink jet printer would typically require an external formatter to format the print job. In addition, due to the minimal complexity in design, the ink jet printer typically would not comprise the ability to track in real-time individual nozzle firings and monitor the time between firings of each nozzle. As such, there is a need for a new method of printing with a hand-held ink jet printer which includes one or more maintenance firings from a printhead nozzle. Accordingly, improved methods of printing are desired.